(b)
Whenusingrechargeunitcontainingone supplycylinder,slowlyopensupplyunitvalveand allowoxygento transferuntil cylinderservicepressureisreached.Ambienttemperaturemust be consideredwhenfilling oxygencylinders. SeeChart 2, IndicatedOxygenCylinder Pressuresvs. AmbientTemperature.
(c)
Whenusingrechargeunit containingtwoor moresupplycylinders(cascadestoragesystem), proceedas follows:
(1.) Beforeopeninganyvalves,checkremainingpressurein airplaneoxygencylinder. If partly charged,note pressureindicatedon cylindergauge. Openandcloseeachvalveon cascadestoragesystemanddeterminewhichcylinderhaslowestpressure. If this cylinderhaspressurelowerthan oxygencylinderin airplane,do not attemptto fill it. Use storagecylinderwith pressurehigherthanairplanecylinder,but lowerthanall others.
(2.) Openvalveonlyon storagecylinderwith lowestpressure.Whenindicatedpressureon airplaneoxygengauge andcharginggaugeis equal,closestoragecylindervalve. Proceedto storagecylinderwith nexthigherpressureandrepeatprocedure.
(3.) After adjustinglast storagecylinder,if oxygensystemis stillnotfully chargedthen place full storagecylinderin placeof cylinderwith lowestpressure.
(4.) Oxygenwill remainin largecylindersusedin cascadesystemsafterfillingonlyone cylinder. Suchremainingoxygenisat a pressurelessthan 1800pounds,whichis not sufficientto completelyrefillanotheraircraftcylinder.
(5.) Donot rechargethree orfour-cylindercascadesystemswith oxygenat lessthan 300 psi pressurein 300 cubicfoot bankof cylinders. Use300cubicfoot cylindersto approximately300 psi and returnfor refilling. In two-cylindersystems,useto approximately600psi and returnforfilling. (SeeChart 2, indicatedOxygenCylinder Pressuresvs. AmbientTemperatures.)
WARNING: BLEEDPRESSUREFROMFILLERHOSEBEFOREDISCONNECTING FROMFILLERVALVE.
(d) Whenpressuregaugeon rechargeunitor in airplanereachesappropriateservicepressure (Chart 3),closepressurevalveon rechargeunit. Disconnectfiller hosefromfillervalve; replaceprotectivecapon filler valveandcloseaccessdoor.
°
NOTE: Thistableaccountsfor about25 raiseintemperaturedue to heatof compressionand presumescylindersarefilledat maximumrate.
EFFECTIVITY:
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PIPERAIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL
Y. OxygenSystem(continued)
2. Filling Oxygen Cylinder (continued)
CHART 2
OXYGEN CYLINDER FILLING PRESSURES VS. AMBIENT TEMPERATURE
AmbientTemperature-°F Filling Pressures -Psig
0 1650 10 1700 20 1725 30 1775 40 1825 50 1875 60 1925 70 1975 80 2000 90 2050 100 2100 110 2150 120 2200 130 2250
NOTE: Pressuresarenot exact, but accurateenough for workingpressuresbetween1800 to 2400 psigcylinders.
CHART 3
INDICATED OXYGEN CYLINDER PRESSURES VS. AMBIENT TEMPERATURE
Ambient Temperature-°F Indicated Cylinder Pressure-Psig
110 1980 100 1935 90 1890 80 1845 70 1800 60
1755 50 1710 40 1665
EFFECTIVITY:
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PIPER AIRCRAFT
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MAINTENANCEMANUAL
A. ScheduledServicing
1. AirframeLubrication
Properlubrication procedures are valuable for prolonging the service life of the airplane and as a
meansof reducing the frequency of extensive and expensive repairs. The periodic application of
recommendedlubricants to relevant bearing surfaces combined with cleanliness, as detailed in the
followingparagraphs,ensuresmaximumefficiency and utmost service of all moving parts.
Lubrication instruction regarding locations, timeintervals, and type of lubricants used are found in
proper lubrication charts. To ensure the best possible results from lubricant application, observe
the following precautions:
(a)
Use only recommended Where general purpose lubricating but
lubricants. oil is specified, unavailable,cleanreciprocatingengineoil is a satisfactory substitute.
(b)
Checkcomponentsfor evidence of excessivewear and replaceas necessary.
(c)
Removalall excess lubricantsfrom components to prevent collecting dirt and sand in quantities capableof causing excessivewearor damage to bearing surfaces.
2. Applicationof Grease
Whenlubricatingbearings and bearing surfaces with a grease gun, ensure gun is filled with new, cleangrease specified for the particular application before applying lubricant to grease fittings.
(a)
If a reservoir is not provided around a bearing, apply lubricant sparingly and wipe off excess.
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